Sắp xếp kết quả

SQL nâng cao

Jasmin Ludolf

Data Science Content Developer, DataCamp

Sắp xếp kết quả

![Một hình minh họa thể hiện hai tủ quần áo đặt cạnh nhau, tủ bên trái có một đống quần áo lộn xộn trong khi tủ bên phải thể hiện một tủ quần áo được sắp xếp gọn https://assets.datacamp.com/production/repositories/6052/datasets/9d4d74fe725d0ad4c292e437137a3ed0bba257c5/sorted.jpggàng.

ORDER BY

SELECT title, budget
FROM films
ORDER BY budget;

|title               |budget|
|--------------------|------|
|Tarnation           |218   |
|My Date with Drew   |1100  |
|A Plague So Pleasant|1400  |
|The Mongol King     |3250  |
...

SELECT title, budget
FROM films
ORDER BY title;

|title                     |budget  |
|--------------------------|--------|
|#Horror                   |1500000 |
|10 Cloverfield Lane       |15000000|
|10 Days in a Madhouse     |12000000|
|10 Things I Hate About You|16000000|
...

ASC - thứ tự tăng dần

SELECT title, budget
FROM films
ORDER BY budget ASC;

|title               |budget|
|--------------------|------|
|Tarnation           |218   |
|My Date with Drew   |1100  |
|A Plague So Pleasant|1400  |
|The Mongol King     |3250  |
...

DESC - thứ tự giảm dần

SELECT title, budget
FROM films
ORDER BY budget DESC;

|title                         |budget|
|------------------------------|------|
|Love and Death on Long Island |null  |
|The Chambermaid on the Titanic|null  |
|51 Birch Street               |null  |
...

SELECT title, budget
FROM films
WHERE budget IS NOT NULL
ORDER BY budget DESC;

|title                  |budget     |
|-----------------------|-----------|
|The Host               |12215500000|
|Lady Vengeance         |4200000000 |
...

Sắp xếp các trường

SELECT title
FROM films
ORDER BY release_year;

|title                                |
|-------------------------------------|
|Intolerance: Love's Struggle Throu...|
|Over the Hill to the Poorhouse       |
|The Big Parade                       |
|Metropolis                           |
...

SELECT title, release_year
FROM films
ORDER BY release_year;

|title                   |release_year|
|------------------------|------------|
|Intolerance: Love's S...|1916        |
|Over the Hill to the ...|1920        |
|The Big Parade          |1925        |
|Metropolis              |1927        |
...

ORDER BY nhiều trường

ORDER BY field_one, field_two

SELECT title, wins
FROM best_movies
ORDER BY wins DESC;

|title                           |wins|
|--------------------------------|----|
|Lord of the Rings:Return of t...|11  |
|Titanic                         |11  |
|Ben-Hur                         |11  |

Xem xétfield_twonhư một yếu tố quyết định

SELECT title, wins, imdb_score
FROM best_movies
ORDER BY wins DESC, imdb_score DESC;

|title                |wins|imdb_score|
|---------------------|----|----------|
|Lord of the Rings:...|11  |9         |
|Ben-Hur              |11  |8.1       |
|Titanic              |11  |7.9       |

Các thứ tự khác nhau

SELECT birthdate, name
FROM people
ORDER BY birthdate, name DESC;

|birthdate |name            |
|----------|----------------|
|1990-01-01|Robert Brown    |
|1990-02-02|Anne Smith      |
|1991-05-14|Amy Miller      |
|1991-11-22|Adam Waters     |
...

Thứ tự thực thi

-- Written code:

SELECT item
FROM coats
WHERE color = `yellow`
ORDER BY length
LIMIT 3;

-- Order of execution:

SELECT item

FROM coats

WHERE color = `yellow`

ORDER BY length

LIMIT 3;

Cùng thực hành nào!

SQL nâng cao